Interior rear view mirrors of the generic kind, in addition to the mirror element for observing the traffic following behind, have an additional device which is mounted adjustably on the housing of the interior rear view mirror. The installation space available within the interior rear view mirror is used for housing the additional device, wherein the additional device can include, for example, a small monitor, or a rack for storage of small parts, or other devices. Known are, for example, interior rear view mirrors with an adjustably mounted video unit which is pulled out when changing into reverse gear and which displays video images of the vehicle interior. Alternatively, in addition, video units mounted on the interior rear view mirror are known by means of which images of the interior camera for observing the passengers within the interior of a motor vehicle can be displayed. Also, navigation displays which are attached to the interior rear view mirror have an increasingly wide distribution.
According to the prior art, the additional devices are pulled out laterally from the interior rear view mirror. In particular, for additional devices with a higher dead weight, such as, for example, video units, this lateral arrangement of the additional devices results in an unfavorable shifting of the center of gravity of the centrically mounted interior mirror. Tests have shown that during the driving operation, primarily vibration forces, which are oriented substantially vertically, are acting upon the interior mirror. Due to the shifting of the center of gravity caused by the additional device, these vertically oriented vibration forces result in the occurrence of visibility distortions due to the increased vibration tendency of the interior rear view mirror. In the worst case, the vibration forces can result in an undesired displacement of the mirror housing by rotation about the longitudinal axis, whereby the driving safety is at risk.